In the late 1980s I bought my first pair of alpha-class binoculars. Although I had never been a fan of high power binoculars, I allowed myself to be swayed by fashion. The Zeiss 10x40s were the “in” binoculars of their day. The old rule about hand-holding long lenses had become old hat. But physics and human anatomy hadn’t changed. Having grown up in the camera business I was well-acquainted with the maxim that (for long lenses) the minimum shutter speed had to be equal to or greater than the focal length of the lens to get sharp photos without a tripod. (For example you had to shoot at at least 1/250 sec. when using a 250mm lens without a tripod because you need a fast shutter speed to freeze the movement of your hands.) The same principal applied to binoculars because magnification enlarges not only the image. It magnifies the movement of your hands by the same factor. There’s no getting around the principal that you will get more useful information from a more stable image than from a less stable one. Although I knew all these things I bought the 10x40s because all the hot young birders were using them and proclaiming that the old rule applied only to old people.

Several years later, while standing in a freezing bird blind at Audubon’s Lillian Annette Rowe Sanctuary in Nebraska, I asked a friend if I could have a look through his Zeiss 7x42s. It was an expensive peek because that look ended my love affair with the 10x40s I had so coveted. The 7s were much brighter. They had a panoramic field of view which made it easier to find and follow birds. They seemed more enjoyable to use because the micro-vibrations of my hands were being magnified by a factor of only 7 rather than 10. The other surprise in the 7x42s was that the 3x difference in magnification didn’t seem to make a difference. Later that spring I bumped into Roger Tory Peterson and Pete Dunne at Cape May and noticed that they were both wearing Zeiss 7x42s. That encounter gave me the confidence to abandon fashion and trade my 10x40s for a pair of 7x42s. I have never looked back.

Despite the laws of optics and human anatomy many more people buy 10x bins than 7x. In fact it has become impossible to convince all but the most knowledgeable buyers to buy 7x bins because most customers instinctively feel that more power must be better and because there are fewer people out there who remember cameras before digital image stabilizers.

Nevertheless, there are lots of experienced and knowledgeable birders who prefer 10x binoculars. If you fall into the 10x camp, this article is for you. For you 10x devotees I have some good news and some bad news. First the good news. Swarovski has added a 10x50 model to its incredible EL SV line. The bad news? If you look through them you will never be content with your current binoculars again, so don’t look or get ready to shell out some shekels.

Since Swarovski’s EL SV lineup already includes a 10x42, why add another 10x model? Because there is another principal of optics which dictates that (all other things being equal) larger objective lenses (the lenses furthest from your eye) will provide a brighter image with higher resolution than will smaller objective lenses. Since nothing is free, you will pay for the improved image with added size and weight. Swarovski’s EL 10x50 SV is 7 ounces heavier than the 10x42, but birders seeking ultimate optical truth will gladly bear the few extra ounces. You will really appreciate these bins in the most demanding viewing conditions -- when looking at shore birds, hawks, or pelagic birds, especially in poor light.

The Swarovski EL 10x50 SV's feature an excellent focusing system, eye relief that shows almost the entire field of view when used with eyeglasses, and enough interpupilary adjustment to match anyone’s needs. The color rendition, resolution, and lack of distortion seem about on par with the EL 8.5x42 SVs which I consider to be the current benchmark for birding binoculars.

What to buy? Despite my preference for 7x bins, I regard the Swarovski EL 8.5x42 SV as the best overall birding binocular on today’s market. If I could afford a second, special use, pair (for hawk watching and pelagic birding) my second pair would be the Swarovski 8x56 SLC which I think offers the best image that I have seen in any binocular. But these are so big and so heavy that nobody would consider them as a primary birding binocular. If I were a fan of 10s, I would buy the EL 10X50 SV as an all around birding binocular and be happy with them until I got too old to hold them.

What should you buy? If you are in the market for binoculars I urge you to look at all the binoculars you are considering. Consider my advice and the advice of others, but don’t buy anything solely on the basis of any one person's advice. Make sure they feel good in your hands. If you wear eyeglasses make sure that you can see all (or most of) the field of view when wearing your eyeglasses. Make sure that you can match the interpupilary distance of the binocular barrels to your eyes. And make sure that you are comfortable with the weight and size of any model you are considering. If you have small hands or have arthritis consider buying an 8x30 mid-sized model.

For those looking for full-sized 10x binoculars the Swarovski EL 10x50 SV should be at the top of the list of models you should consider.

Wayne Mones
Sept. 7, 2011

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